[RF69] Implemented getPacketLength

examples/RF69/RF69_Transmit/RF69_Transmit.ino

@@ -59,11 +59,11 @@ void loop() {
 
   if (state == ERR_NONE) {
     // the packet was successfully transmitted
-    Serial.println(F(" success!"));
+    Serial.println(F("success!"));
 
   } else if (state == ERR_PACKET_TOO_LONG) {
     // the supplied packet was longer than 64 bytes
-    Serial.println(F(" too long!"));
+    Serial.println(F("too long!"));
 
   } else {
     // some other error occurred

src/modules/RF69.cpp

@@ -1,8 +1,9 @@
 #include "RF69.h"
 
-RF69::RF69(Module* module) : PhysicalLayer(RF69_CRYSTAL_FREQ, RF69_DIV_EXPONENT)  {
+RF69::RF69(Module* module) : PhysicalLayer(RF69_CRYSTAL_FREQ, RF69_DIV_EXPONENT, RF69_MAX_PACKET_LENGTH)  {
   _mod = module;
   _tempOffset = 0;
+  _packetLengthQueried = false;
 }
 
 int16_t RF69::begin(float freq, float br, float rxBw, float freqDev, int8_t power) {
@@ -102,7 +103,7 @@ int16_t RF69::transmit(uint8_t* data, size_t len, uint8_t addr) {
 
 int16_t RF69::receive(uint8_t* data, size_t len) {
   // start reception
-  int16_t state = startReceive();
+  int16_t state = startReceive(true);
   if(state != ERR_NONE) {
     return(state);
   }
@@ -191,27 +192,31 @@ int16_t RF69::disableAES() {
   return(_mod->SPIsetRegValue(RF69_REG_PACKET_CONFIG_2, RF69_AES_OFF, 0, 0));
 }
 
-int16_t RF69::startReceive() {
+int16_t RF69::startReceive(bool timeout) {
   // set mode to standby
   int16_t state = setMode(RF69_STANDBY);
 
-  // set DIO pin mapping
+  // set RX timeouts and DIO pin mapping
-  state |= _mod->SPIsetRegValue(RF69_REG_DIO_MAPPING_1, RF69_DIO0_PACK_PAYLOAD_READY, 7, 6);
+  if(timeout) {
-
+    state = _mod->SPIsetRegValue(RF69_REG_DIO_MAPPING_1, RF69_DIO0_PACK_PAYLOAD_READY | RF69_DIO1_PACK_TIMEOUT, 7, 4);
-  // clear interrupt flags
+    state |= _mod->SPIsetRegValue(RF69_REG_RX_TIMEOUT_1, RF69_TIMEOUT_RX_START);
-  clearIRQFlags();
+    state |= _mod->SPIsetRegValue(RF69_REG_RX_TIMEOUT_2, RF69_TIMEOUT_RSSI_THRESH);
-
+  } else {
-  // disable RX timeouts
+    state = _mod->SPIsetRegValue(RF69_REG_DIO_MAPPING_1, RF69_DIO0_PACK_PAYLOAD_READY, 7, 6);
-  state |= _mod->SPIsetRegValue(RF69_REG_RX_TIMEOUT_1, RF69_TIMEOUT_RX_START_OFF);
+    state |= _mod->SPIsetRegValue(RF69_REG_RX_TIMEOUT_1, RF69_TIMEOUT_RX_START_OFF);
-  state |= _mod->SPIsetRegValue(RF69_REG_RX_TIMEOUT_2, RF69_TIMEOUT_RSSI_THRESH_OFF);
+    state |= _mod->SPIsetRegValue(RF69_REG_RX_TIMEOUT_2, RF69_TIMEOUT_RSSI_THRESH_OFF);
+  }
   if(state != ERR_NONE) {
     return(state);
   }
 
+  // clear interrupt flags
+  clearIRQFlags();
+
   // set mode to receive
-  state = setMode(RF69_RX);
+  state = _mod->SPIsetRegValue(RF69_REG_TEST_PA1, RF69_PA1_NORMAL);
-  state |= _mod->SPIsetRegValue(RF69_REG_TEST_PA1, RF69_PA1_NORMAL);
   state |= _mod->SPIsetRegValue(RF69_REG_TEST_PA2, RF69_PA2_NORMAL);
+  state |= setMode(RF69_RX);
 
   return(state);
 }
@@ -226,7 +231,7 @@ void RF69::setDio1Action(void (*func)(void)) {
 
 int16_t RF69::startTransmit(uint8_t* data, size_t len, uint8_t addr) {
   // check packet length
-  if(len > 64) {
+  if(len > RF69_MAX_PACKET_LENGTH) {
     return(ERR_PACKET_TOO_LONG);
   }
 
@@ -264,7 +269,10 @@ int16_t RF69::startTransmit(uint8_t* data, size_t len, uint8_t addr) {
 
 int16_t RF69::readData(uint8_t* data, size_t len) {
   // get packet length
-  size_t length = _mod->SPIreadRegister(RF69_REG_FIFO);
+  size_t length = len;
+  if(len == RF69_MAX_PACKET_LENGTH) {
+    length = getPacketLength();
+  }
 
   // check address filtering
   uint8_t filter = _mod->SPIgetRegValue(RF69_REG_PACKET_CONFIG_1, 2, 1);
@@ -273,12 +281,6 @@ int16_t RF69::readData(uint8_t* data, size_t len) {
   }
 
   // read packet data
-  if(len == 0) {
-    // argument len equal to zero indicates String call, which means dynamically allocated data array
-    // dispose of the original and create a new one
-    delete[] data;
-    data = new uint8_t[length + 1];
-  }
   _mod->SPIreadRegisterBurst(RF69_REG_FIFO, length, data);
 
   // add terminating null
@@ -287,6 +289,9 @@ int16_t RF69::readData(uint8_t* data, size_t len) {
   // update RSSI
   lastPacketRSSI = -1.0 * (_mod->SPIgetRegValue(RF69_REG_RSSI_VALUE)/2.0);
 
+  // clear internal flag so getPacketLength can return the new packet length
+  _packetLengthQueried = false;
+
   // clear interrupt flags
   clearIRQFlags();
 
@@ -443,9 +448,9 @@ int16_t RF69::setFrequencyDeviation(float freqDev) {
 
   // set frequency deviation from carrier frequency
   uint32_t base = 1;
-  uint32_t FDEV = (freqDev * (base << 19)) / 32000;
+  uint32_t fdev = (freqDev * (base << 19)) / 32000;
-  int16_t state = _mod->SPIsetRegValue(RF69_REG_FDEV_MSB, (FDEV & 0xFF00) >> 8, 5, 0);
+  int16_t state = _mod->SPIsetRegValue(RF69_REG_FDEV_MSB, (fdev & 0xFF00) >> 8, 5, 0);
-  state |= _mod->SPIsetRegValue(RF69_REG_FDEV_LSB, FDEV & 0x00FF, 7, 0);
+  state |= _mod->SPIsetRegValue(RF69_REG_FDEV_LSB, fdev & 0x00FF, 7, 0);
 
   return(state);
 }
@@ -556,6 +561,15 @@ int16_t RF69::getTemperature() {
   return(0 - (rawTemp + _tempOffset));
 }
 
+size_t RF69::getPacketLength(bool update) {
+  if(!_packetLengthQueried && update) {
+    _packetLength = _mod->SPIreadRegister(RF69_REG_FIFO);
+    _packetLengthQueried = true;
+  }
+
+  return(_packetLength);
+}
+
 int16_t RF69::config() {
   int16_t state = ERR_NONE;
 

src/modules/RF69.h

@@ -9,6 +9,7 @@
 // RF69 physical layer properties
 #define RF69_CRYSTAL_FREQ                             32.0
 #define RF69_DIV_EXPONENT                             19
+#define RF69_MAX_PACKET_LENGTH                        64
 
 // RF69 register map
 #define RF69_REG_FIFO                                 0x00
@@ -580,9 +581,11 @@ class RF69: public PhysicalLayer {
     /*!
       \brief Interrupt-driven receive method. GDO0 will be activated when full packet is received.
 
+      \param timeout Enable module-driven timeout. Set to false for listen mode.
+
       \returns \ref status_codes
     */
-    int16_t startReceive();
+    int16_t startReceive(bool timeout = false);
 
     /*!
       \brief Reads data received after calling startReceive method.
@@ -694,6 +697,15 @@ class RF69: public PhysicalLayer {
     */
     int16_t getTemperature();
 
+     /*!
+      \brief Query modem for the packet length of received payload.
+
+      \param update Update received packet length. Will return cached value when set to false.
+
+      \returns Length of last received packet in bytes.
+    */
+    size_t getPacketLength(bool update = true);
+
   protected:
     Module* _mod;
 
@@ -701,6 +713,9 @@ class RF69: public PhysicalLayer {
     float _rxBw;
     int16_t _tempOffset;
 
+    size_t _packetLength;
+    bool _packetLengthQueried;
+
     int16_t config();
     int16_t directMode();